In a D+2 Marist poll, President Barack Obama and Mitt Romney are tied (48%-48%) in Colorado, a state Obama led by five points in the same poll after the Democratic National Convention and before the debates. But the momentum among nearly every demographic is on Romney's side. 

Obama won Colorado by nine points in 2008 largely because of independent suburban white voters, but, as Marist notes, he is "losing suburban Denver voters as well as independents to Romney." Romney has also closed the gender gap, and young voters are not as enthusiastic for Obama as they had been just a month ago. 

According to Marist, Obama "led by 18 points among Denver suburban women" a month ago but now leads by three points.

Among suburban men, Romney led by six points a month ago and now leads by 13.

Obama last month led Romney among independents and women by 11 and 14 points, respectively. Now, Obama leads by only one point among independents and seven points among women.

What a difference a month -- and three debates -- makes.